The use of coronary catheters in selective coronary arteriography procedures for the identification and evaluation of arterial blockage in major coronary arteries is well known. This evaluation is carried out by means of injection of a radiopaque tracer media through a flexible catheter into a coronary artery and thereafter monitoring the fluid flow characteristics exhibited within that artery by means of X-ray imagery as the radiopaque tracer is transported with the blood through the artery under evaluation.
As will be readily recognized, the introduction of both the catheter and the radiopaque media to the vessel under evaluation must be carried out without trauma to either the heart muscle itself or the blood vessels within the heart. In order to gain access to the coronary arteries without damaging the area to be studied, a hollow flexible catheter is introduced into a major blood vessel in an area of the body remote from the heart and guided to the coronary artery to be studied. The radiopaque tracer is then injected through the catheter and into the artery under evaluation.
In carrying out coronary arteriography of a right coronary artery, a percutaneous entry is typically made at the femoral artery. Catheters used in conjunction with a femoral approach include the Amplatz and the Judkins configurations (FIGS. 6 and 7, respectively) wherein the catheter tip is oriented at substantially a 90.degree. angle to the adjacent section of the catheter body. In a femoral artery approach procedure, a guidewire is generally threaded to a point above the aortic bifurcation. The catheter is inserted over the guidewire and the catheter and guidewire are eased up the aorta until the tip of the guidewire reaches the distal portion of the coronary arch. At this stage, the guidewire is generally removed and the flexible catheter is advanced over the coronary arch and manipulated to engage the tip of the catheter with the orifice of the right coronary artery.
Since the catheter in a femoral approach procedure must be advanced through the aortic arch and inserted into the orifice of the coronary artery, the catheter must cooperate with the anatomical configuration of the arch and orifice. Accordingly, catheters have typically been fabricated from low temperature thermoplastic materials such as polyurethane which have inherent pliability and elasticity. In addition, catheters have typically been preshaped to conform to the arch and coronary artery anatomies generally encountered, with different sizes being available for patients with anatomical variations in the aortic root arising from differences in age, weight, disease, and other physical characteristics.
Moreover, the combined need to easily pass the catheter over the coronary arch while at the same time having the catheter conform to the anatomy of the coronary arch and artery orifice once in place has heretofore presented significant difficulty with respect to catheterization of the right coronary artery. The right coronary artery is situated on the outer perimeter of the ascending aorta past the coronary arch, thereby preventing easy insertion of the catheter tip as it travels along the natural curve of the arch.
Prior to the present invention, the solution to this difficulty has been to equip the catheter with a tip portion bent at approximately 90.degree. to the adjacent body portion of the catheter. The catheter was then advanced through the coronary arch with the tip portion directed towards the axis of curvature of the arch (i.e.. away from the right coronary artery orifice), thereby facilitating passage through the arch. After the tip portion had passed substantially over the coronary arch, the entire catheter was rotated approximately 180.degree. to bring the catheter tip into contact with the orifice of the right coronary artery. Performing this rotation, however, requires considerable skill and gives rise to a serious potential for vessel trauma as the tip of the catheter sweeps, sometimes with a whipping action, into place.
Despite the existence of right coronary catheters for use in selective coronary arteriography which may be inserted directly into the orifice of the right coronary artery by means of a brachial approach procedure, or which may be rotated into position after being guided over the aortic arch in a femoral artery approach procedure, there remains a need for a right coronary catheter which may be inserted directly into the orifice of the right coronary artery by means of a femoral artery approach procedure without rotation of the catheter while in the coronary arch. There is also a need of a right coronary catheter which is of a substantially universal size which can be used with most patients.